AT295692B - Water-soluble coating agent - Google Patents

Description

  

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  Water-soluble coating agent The aqueous coating agent according to the parent patent contains as binder A) one or more carboxyl group-bearing reaction products of diene polymers
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 drides and / or half esters and / or half amides, B) one or more, optionally etherified, heat-reactive condensation products of formaldehyde with phenolcarboxylic acids, optionally additional condensation products of formaldehyde with phenols and / or ureas and / or aminotriazines, and optionally
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Molecular weight between 50 and 3,000.



   As stated in the description of the parent patent, binders that contain reaction products of diene polymers with maleic anhydride tend to skin formation during storage compared to those made from drying oils due to the generally higher oxygen reactivity, and coatings made from them show too rapid surface drying and therefore lack of oxidative penetration - hardening.



   The content of component B) and, to a lesser extent, also component C), the oxygen reactivity of the binder is reduced.



   It has not been found that, as a modification of the above embodiment, coating agents can be produced which are also characterized by low oxygen reactivity if component A) is reacted together with diene polymers and modified or unmodified unsaturated fatty acids with more than 8 carbon atoms with o , ß-ethylenically unsaturated carboxylic acids and / or dicarboxylic acids and / or their anhydrides and / or half-esters and / or half-amides.



   The invention thus relates to aqueous coating compositions, consisting of a binder which is water-soluble after neutralization with ammonia or an organic and / or inorganic base, water, and optionally a water-tolerant solvent, the binder being composed of
A) carboxyl group-bearing reaction products from 0;

   13-Ethylenically unsaturated carboxylic acids and / or dicarboxylic acids and / or their anhydrides and / or half esters and / or half amides with diene polymers and unmodified and / or modified unsaturated fatty acids with more than 8 carbon atoms and one Iodine number of at least 80, B) one or more, optionally etherified, heat-reactive condensation products of formaldehyde with phenolcarboxylic acids, optionally additional condensation products of formaldehyde with phenols and / or ureas and / or aminotriazines, and optionally
C)

   one or more polyhydroxyl compounds having at least two hydroxyl groups and one
Molecular weight between 50 and 3,000

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 a lacquer paste produced on a three-roll mill. After neutralization with triethylamine to a pH of 7.5, the mixture is diluted with deionized water to a solids content of 10 to 15%. The anodic deposition takes place in a known manner on degreased sheet metal. The coating cures for 30 minutes at 180 C.



   Lacquer technical properties:
Layer thickness: 20 p; Salt Spray Test ASTM B 117-61; after 300h under 4mm (on not pretreated
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 12 g of Cu naphthenate solution in xylene (1% metal content), 100 g of maleic anhydride and 280 g of polybutadiene (80% cis content, molecular weight about 1500) are added to this prepolymerized fatty acid.



  It is held at 200oC until the free maleic anhydride content has dropped to zero. After cooling to 80 ° C., a mixture of 55 g of diacetone alcohol, 40 g of distilled water and 2 g of triethylamine is added and the mixture is stirred for 2 hours. The resin formed is then diluted with 150 g of ethylene glycol monoethyl ether. 50 g of resolcarboxylic acid are added as component B). A 68% strength resin solution is obtained.



   Resolcarboxylic acid is the partial product Ic) according to Austrian Patent No. 198 858 and is produced as follows:
228 g of diphenylolpropane are dissolved in 500 cm3 of 2N sodium hydroxide solution with the supply of heat. Then the solution of 110 g of sodium monochloroacetate (technical grade) in 170 g of water is added, the temperature is slowly increased to 40 to 90 ° C. and the reaction mixture is kept under constant stirring for 1 h.



   After cooling and removing the upper thin aqueous layer, the weight of the reaction mass is around 600 g. The part of a sample freed from alkali by acidification, which is soluble in a mixture of toluene and butanol, shows from the acid number that about 85% of the diphenylolpropane has been converted, while the rest has remained free.



   The mass is combined with 200 g of formaldehyde, 35% strength, to form a clear solution and kept at about 40 ° C. for 3 days. The mixture of resolcarboxylic acid and resol is then precipitated in the presence of 100 g of butanol with the calculated amount of hydrochloric acid. After washing out several times and allowing it to sit well, about 500 g of butanolic solution are obtained. The solids content is around 340 g and has an acid number of around 140 mg KOH / g. After neutralizing the solution with ammonia, it can be diluted indefinitely with water.



   To produce a varnish, the procedure is analogous to Example 2 and films with equally good properties are obtained.



   Example 4: 173 g of tall oil fatty acid with 1% resin acid content are admixed with a mixture of 43 g of styrene and 1 g of di-tert-butyl peroxide at 160 ° C. over the course of 90 minutes. The temperature is increased to 3000C in 2 hours and this temperature is maintained for a further 4 hours.



   After cooling to 100 ° C., 100 g of maleic anhydride, 12 g of Cu naphthenate solution in xylene (1% metal content) and 264 g of polybutadiene (80% cis content, molecular weight about 1500) are added. The temperature is maintained at 200 ° C. until the free maleic anhydride content has fallen to zero.



   At 90 ° C., the mixture is hydrolyzed with 20 g of water and 1 g of triethylamine for 2 hours. It is neutralized with ammonia until it is completely soluble in water (p # value 7.3) and it is diluted with distilled water to a solids content of 40%. H
250 g resin solution (40%) are pigmented with 30 g TiO and 0.5 g carbon black and diluted with a further 700 g distilled water. The deposition takes place analogously to Example 2. The properties of the film correspond to those of Example 2.



     Example 5: For comparison, a binder without the modification according to the invention is produced as follows:
400 g of polybutadiene (80% cis content, molecular weight about 1500) are heated to 2000C together with 12 g of Cu naphthenate solution in xylene (1% metal content) and 100 g of maleic anhydride until the content of free maleic anhydride has dropped to zero. After cooling to 90 ° C., the mixture is hydrolyzed with 20 g of water and 2 g of triethylamine for 2 hours at 90 ° C. It is diluted with 200 g of ethylene glycol monoethyl ether.



   The resin solution is pigmented and neutralized as in Example 2.

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   Comparison of the quality of the surface of electrophoretically deposited films before and after curing:
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<tb> before <SEP> the <SEP> hardening <SEP> after <SEP> the <SEP> hardening
<tb> Example <SEP> 2 <SEP> dense, <SEP> smooth <SEP> film,
<tb> example <SEP> 3 <SEP> dry <SEP> adhesive,
<tb> Example <SEP> 4 <SEP> coating, <SEP> fully hardened.
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  Example <SEP> 1 <SEP> of the <SEP> adhesive,
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<tb> Example <SEP> 5 <SEP> gelatinous <SEP> Ab- <SEP> wrinkled <SEP> film,
<tb> separation, <SEP> not <SEP> bad <SEP> continuous, <SEP> bad <SEP> hardens, <SEP> little <SEP> wettable, <SEP> firm.
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Claims (1)

<Desc / Clms Page number 6> common reaction product of ct, ss-ethylenically unsaturated carboxylic acids and / or dicarboxylic acids and / or their anhydrides and / or their half-esters and / or their half-amides with diene polymers and hydroxyl-free condensation products of isocyanates with partial polyol esters of unsaturated fatty acids. 8. Coating agent according to claim l, characterized in that component A) is a common reaction product of tx, ß-ethylenically unsaturated carboxylic acids and / or dicarboxylic acids and / or their anhydrides and / or their half-esters and / or their half-amides with diene polymers, unmodified and / or modified fatty acids with more than 8 carbon atoms and an iodine number of at least 80 and colophony.